Any extremely deadly trap, puzzle, or predicament in a Dungeons & Dragons adventure. Named for Gary Gygax, creator of D&D and known to create some exceedingly lethal adventure modules, especially the traps.

That acid spray trap on that chest was quite gygaxian.

As pertaining to Gary Gygax, late co-creator of Dungeons and Dragons. Noted for extremely lethal traps and puzzles which rewarded the player for proceeding with paranoid caution. Frequently resulting in total party kills or instant death or dismemberment of a character.

Gygaxian dungeon design is credited with the boom in sale of 10-ft poles and halfling "trap springer" rogues.